The present invention relates generally to automotive vehicle convertible roofs and more particularly to a convertible vehicle top stack mechanism having an active rearmost roof bow.
Some traditional convertible roofs for automotive vehicles employ an active number five bow which can be selectively rotated from a nominal and generally horizontal position to a raised and generally vertical position in order to allow clearance for a moveable, rigid tonneau cover. Such a tonneau cover needs to be opened to allow convertible roof access for retraction into a storage compartment or boot well, and the tonneau cover is closed so the number five roof bow can sit on top of it when the convertible roof is fully raised. One such example is disclosed in U.S. Pat. No. 6,039,382 entitled “Folding Top for a Motor Vehicle” which issued to Mather et al., on Mar. 21, 2000, and is incorporated by reference herein.
Hydraulically driven buggy links have been used to move active number five roof bows in various of these conventional roof systems. Some exemplary U.S. patents disclosing these conventional constructions are: U.S. Pat. No. 5,816,644 entitled “Folding Top for a Convertible” which issued to Rothe et al. on Oct. 6, 1998; and U.S. Pat. No. 5,749,619 entitled “Motor Vehicle with Foldable Roof, and Foldable Roof for Such a Motor Vehicle” which issued to Mentink on May 12, 1998; both of these are incorporated by reference herein. It is noteworthy, however, that many traditional number five bow actuation systems have required undesirably high forces to operate which necessitates difficult to package, large and expensive hydraulic cylinders while increasing the chance of premature part failure. Furthermore, many of these traditional systems disadvantageously create undesirably fast acceleration of the number five bow during movement which can lead to premature part failure.
In accordance with the present invention, a convertible vehicle top stack mechanism includes a moveable rearmost roof bow and an actuator. In an other aspect of the present invention, a linkage assembly couples a rearmost roof bow to a side rail. A further aspect of the present invention employs a rotatable member or crank to drive a set of buggy links in order to raise and lower an active number five roof bow. Yet another aspect of the present invention employs an automatic actuator which has an elongated dimension generally parallel to a rear side rail of a top stack mechanism.
The convertible vehicle top stack mechanism of the present invention is advantageous over traditional constructions in that the present invention reduces the activation forces required to move a rearmost roof bow relative to a side rail while also reducing acceleration spikes during movement of the rearmost roof bow. The present invention is further advantageous by providing a more modularized and integrated package for the top stack mechanism to facilitate and ease assembly of same into an automotive vehicle body. For example, the automatic actuator is preassembled to the top stack mechanism prior to shipment to the customer's final assembly plant such that a portion of the actuator does not need to be subsequently fastened to the automotive vehicle body. Accordingly, the present invention reduces part failure during usage, is easier to control, and is simpler to package and install in the vehicle. Additional advantages and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.